By definition forgiveness of sins saves a person, for where the sins are forgiven, there is no accusation, and if there is no accusation there is no condemnation.
Water baptism on the other hand, is a ceremony that symbolizes the death to sin and rebirth, and it is a public testimony. As such it fulfills Christ command to acknowledge him before others and his command to baptise as part of the great commission.
The water baptism ceremony was commanded, but in most verses that deal with eternal life or salvation only belief in Jesus is mentioned. No additional conditions other than belief is mentioned. Again this belief is not mere mental ascent to Jesus' identity but a trusting faith.
There are a couple of verses that mention baptism in connection with salvation, but in light of the numerous other passages, baptism does not appear to actually be a requirement of salvation, but rather a command to be performed immediately after salvation.
And there are two baptisms, there is the water baptism, and the spiritual baptism. The spiritual baptism occurs the instant you accept Jesus. Everyone who has accepted Jesus as Savior has been baptised in the Spirit.
Acts 11:16 Then I remembered what the Lord had said: 'John baptized with [ Or in] water, but you will be baptized with the Holy Spirit.'
> 1 Peter 3:21 and this water symbolizes baptism that now saves you also—not the removal of dirt from the body but the pledge [ Or response] of a good conscience toward God. It saves you by the resurrection of Jesus Christ,
In Acts 10:44-48, the Holy Spirit fell on the Gentiles when they believe before water baptism had occured.
1 John 1:7 says "But if we walk in the light,...." In the very next chapter, 1 John 2:19 talks about some people who left the faith. John says they were never one of us to begin with, and the fact that they left, proves that they were never Christian to begin with, because if they were Christian they wouldn't have fallen away. You're either entered the light or you haven't, you've either known Christ or you've never known him. Christ is in you or He's not, there is no inbetween or in and out. And again this echoes what Jesus says He will say to the unrighteous, "I never knew you."
John also writes this 1 John 5:13 I write these things to you who believe in the name of the Son of God so that you may know that you have eternal life.
We as Christians should KNOW that we have eternal life. It's not something that we should be going around doubting or worrying that God is going to reject us after having adopted us, because to do so, is to put our faith in our own works instead of in Jesus.
John 6:37 All that the Father gives me will come to me, and whoever comes to me I will never drive away.
According to Paul in Ephesians 4:5, there is only one baptism that is connected with being in the body of Christ. Of the 2 baptisms we read about in the New Testament, spirit baptism and water baptism, only one was commanded. It is water baptism. It is also the only baptism that can be administered by man. This is the baptism that Paul is speaking about in Ephesians 4:5.
Also, with regards to 1 Peter 3:21, Peter is not saying that water baptism symbolizes spirit baptism. If read in context, we see that the waters of the flood, in which Noah and his family were saved, symbolize the waters of baptism which “now save us”. The phrase “this water” in verse 21 is referring to the water of the flood.